Rotary driving mechanism



FIG.

Aug. 13, 1946.

I ROTARY DRIVING MECHANISM Filed April 22, 1943 WORK CCT- v 3 N J 2 ,13% Q Ln INVENTOR RE'MALL/NA wam ' ATTORNEY R.- F. MALLINA 2,405,588

Patented Aug. 13, 1946 glosses ROTARY DRIVING MECHANISM Rudolph F.Mallina, Hastings on Hudson, N. Y.,

assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y.,a corporation of New York Application April 22, 1943, Serial No. 484,096

Claims.

This invention relates to rotary driving mechanism and the object of theinvention is a decoupling and recoupling means whereby a driven membermay be disconnected from its drive and stopped at any instant and thenquickly reconnected to the driving member in exactly its originalangular relationship with the driving member.

According to the invention, the driven member is connected to the drivein accurately predetermined angular relationship by an electricallycontrolled latching device and carries an armature which normallyrotates freely with respect to stationary magnetic braking means.

Th driven member may be brought to rest at any desired instant byoperating a control key which releases the latching device andsimultaneously energizes the magnetic brake. When the key is released,the brake is deenergized and the driven member is recoupled to the driveby a motor which rotates the driven member in the proper direction toengage it with the latching device with minimum travel. This saving oftime in the recoupling operation is effected by means of directioncontacts in the motor circuit which are closed selectively in accordancewith the angular displacement of the driven member from thepredetermined angular relationship.

In the drawing, Fig. 1 is a rotary driving mechanism according to theinvention and Fig. 2 is a developed view showing the latching mechanismand the cam which controls the recoupling motor.

The mechanism of this invention may be used for various purposes but inthe embodiment shown by way of illustration, the potentiometers l and 2are normally rotated to produce cyclically varying voltages in the workcircuits 3 and 4, respectively. The motor 5 drives the shaft 6 directly.

through suitable reduction gearing l and drives the shaft 8 indirectlyand intermittently through the latching device 9 rotating with the gearIll. The device 9 comprises an electromagnet ll having a pivotedarmature l2 which is held by magnetic attraction in the position shownwith the tapered end of the armature engaging the V notch I3 in ring I4which is secured to the shaft 8.

The shaft 8 also carries an annular magnetic ring armature l5 andextends to the arm of the potentiometer 2 through a stationaryelectromagnet 16 mounted on the frame I! of the apparatus. The gear [0is provided with a reversing switch l8 which is operated by the camfollower IS in cooperation with the cam 26 on the shaft 8. The switch I8is preferably of a type which, when operated to open one contact,automatically closes tice the follower 19 would be relatively short andso light as to be easily held in contact with the cam, as for example,by the restoring force of the deflected contact spring 2 i. Similarly anappreoiable spacing is shown between the armature l5 and the body of theelectromagnet l6 but in practice when electromagnet is energized, the

usual axial motion of the shaft 8 may be practically eliminated byplating the inner face of the armature with chromium to provide amagnetic separator in which case the armature may rotate in contact oron the verge of contact with the body of the magnet as in the structureshown in Patent 2,003,913 to Wente.

The shaft 8 is connected through suitable gearing to a recoupling motor22 which is of the conventional reversing type with its reversing wires23, 24, 25 connected through slip rings 26, 21 and 28 on the shaft 6, tothe contacts of the switch I8. Similar rings 29 to 32 are provided forthe external connections to the latching device 9.

With the apparatus in the condition shown, the motor 5 is driving bothpotentiometers but the circuit to motor 22 is open at contact 33 of thelatching device. When the key 34 is depressed, the breaking of contact35 opens the energizing circuit of the magnet l whereupon the spring 33retracts the armature I2 from the notch l3 and closes contacts 33. Thisdisconnects the shaft 8 from the motor 5 but the circuit of motor 22remains open due to the opening of contact 31 on the key 34. The closingof contact 38 on the key energizes the magnet 16 which attracts thearmature i5 and arrests the rotation of the potentiometer 2. Inapparatus of this type, the potentiometers are usually driven at verylow speeds such as oneor two revolutions per minute and by proper timingof the operation of the contacts of the key 34, the shaft 8 is stoppedalmost instantaneously.

When the potentiometer 2 is to be reconnected to the drive, the key 34is released thereby opening at contact 38 the circuit of the brakingmagnet IE and closing at contact 35, the circuit of the latching magnetH which forces the arma ture 42 into sliding contact with the ring 14.In this position of the armature I2 contact 33 remains closed as shownin Fig. 2 and the closing of contact 31 on the key 34 completes thepower In order to recouple the shaft 8 to the shaft 5 in the minimumtime, the direction of'rotation of the shaft 8 during this recouplingoperation should be opposite to the direction of rotation of the shaft 6except when at the instant the key 34 is released, the moving armaturehas passed but is still relatively near the notch l3 in the thenstationary ring It.

The cam on the shaft 8 is therefore shaped so that the switch 18 isclosed to the left to connect conductors 24 and together to giveoppositerotation to the shaft 8- during the major part of a revolutionof the gear I0 with respect to the cam.

The follower I9 is mounted on the gear Iii diametrically opposite thearmature I2 and with shaft 8 in the position shown in Fig; l. Thefollower isengaging the cam 20 at a point adjacent the-elevated position39. If when the key 34 is released, the shaft 6 has rotated onlyslightly beyond the notch l3 as shown in Fig. 2, the follower [9 will beon this elevated portion 39 of the cam, the switch l8 will be closed tothe right and the motor 22 will drive to shaft 8 in the same directionas shaft 6 until the notch I3 overtakes the armature 12. However, if,when the key 34 is released, the armature has rotated so far beyond thenotch that the follower i 9 is contacting' the lower portion of the cam,the switch I8 will be closed to the left' and the motor 22 will drivethe shaft 8 in the clockwise direction (as viewed in Fig. 1) until thenotch 13 meets the armature l2. Gne end of the elevated portion of thecam should be aligned with the notch it as shown inFig. 2 but theproportion of the total circumference of the cam 23 over which theelevated portion 39 extends may, of course, be varied to suit theconditions of the particular case.

In the mechanism shown, the rotor of motor 22- is driven by the shaft 8when that shaft is connected to the gear l0. tionable the shaft of thismotor may be provided with a. conventional electromagnetic clutch whichis engaged only when the shaft 8 is disconnected from the gear in. Thismaybe effected for example by energizing the clutch through contact 380itherkey 34.

Whati's claimed is:

I. In a rotary drive, a rotating drive shaft and a. driven membercapable of rotating together for If this load is. objec- 31 an unlimitednumber of revolutions, a latching device connecting the shaft to themember in predetermined angular relation, magnetic braking means for thedriven member, a switch, means operative in one position of the switchat any angular position of the driven member for releasing the latchingdevice and energizing the braking means and restoring means operative inanother position of the switch for rotating the member into engagementwith the latching device to restore the predetermined angular relationbetween the shaft and the member.

2. A drive, according to claim 1, having contacts operated in accordancewith the angular relationship betwen" the shaft and the member fordetermining the direction of rotation of the restoring means.

3. In a rotary drive, a rotating drive shaft and a driven shaft capableof rotating together for an unlimited number of revolutions, means forcoupling the shafts in predetermined angular relation comprising a ringhaving a notch mounted on-one of the shafts and alatching device mountedonthe other shaft and engaging the notch in the ring, braking means forthe driven shaft, switching means operable at any point in the rotationof the driven shaft to disengage the latching device and energize thebraking means to stop the driven shaft, means for driving the drivenshaft to reengage the latching device,- a control circuit therefor andmeans operated upon the reengagement of the latching device fordisabling thedriving means. I

4. A drive, according to claim 3,. inwhicn the driving means is a motor,in combination with contacts mounted onone of the shafts for reversingthe direction of rotation of the driving means, a cam mounted on theother shaft and means cooperating with the cam for selectively operatinthe contacts to conditionthe driving means for rotation in one directionwhen the drive shaft islagging with respect to the driven shaft and forrotation in the other direction when the drive shaft is leading withrespect to the-driven shaft.

5. In arotary drive, a rotating drive shaft, a driven. shaftcoupled'thereto in predetermined angular relationship, a switch meansactuated in one position of the switch for decoupling and stopping thedriven shaft substantially instantaneously, means actuated in anotherposition of the switch for rotating the driven shaft into thepredetermined angular relationship with the drive shaft, and means:operated in accordance with the angular displacement of. the. shaftsfrom the predetermined: relationship for determining the direction ofrotation of the driven shaftwhen the switch is moved into said otherposition,

RUDOLPH F. MALLINA.

